Each of a lens shutter device, a stop device, and a filter device, used in a camera, has a single blade member or a plurality of blade members so that they are reciprocated by an actuator. Each of these devices is sometimes constructed as an independent unit, but at least two of them may be constructed as one unit. Such lens shutter devices are often designed so that two blades are used. However, in cameras of small lens diameters, a single blade may be used. In the case of stop devices incorporated in the cameras of small lens diameters, it is customary that a single blade having a small circular aperture is moved in and out of a photographing optical path when the necessity arises.
Filter devices, in many cases, are provided with a single blade similar in shape to the blade of the stop device (however, its aperture may have almost the same size as an aperture for regulating a photographing optical path, provided in a base plate) and are mounted, with an ND filter plate so as to cover the aperture in the proximity of the aperture. However, an alternative structure is also proposed in which two blades, each having the above shape, are provided and the blade of the ND filter plate is sandwiched between them so as to cover their apertures, and these three blades are rotated reciprocatably in the same direction simultaneously by the same angle.
The recent tendency of portable information terminals, such as mobile phones and PDAs, is that they are equipped with cameras. However, even though the shutter devices, the stop devices, and the filter devices, mentioned above, are downsized, there is a limit to downsizing of the actuator and an arrangement in the terminal is not easy. In addition, it is not admitted that the portable information terminal itself is oversized for the reason that the devices mentioned above are incorporated. Thus, it is understood that when these devices are incorporated, an image of good quality is obtained, but in practice, it is the present condition that they are not incorporated. (Refer to, for examples, Patent References 1 and 2 described below.)
Patent Reference 1: Japanese Patent Laid open publication No. 2001-309003
Patent Reference 2: Japanese Patent Laid open publication No. 2003-219229